69 lines
2.1 KiB
JavaScript
69 lines
2.1 KiB
JavaScript
'use strict';
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const browserslist = require('browserslist');
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const { isSupported } = require('caniuse-api');
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const fromInitial = require('./data/fromInitial.json');
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const toInitial = require('./data/toInitial.json');
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const initial = 'initial';
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// In most of the browser including chrome the initial for `writing-mode` is not `horizontal-tb`. Ref https://github.com/cssnano/cssnano/pull/905
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const defaultIgnoreProps = ['writing-mode', 'transform-box'];
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/**
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* @type {import('postcss').PluginCreator<void>}
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* @return {import('postcss').Plugin}
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*/
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function pluginCreator() {
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return {
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postcssPlugin: 'postcss-reduce-initial',
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/** @param {import('postcss').Result & {opts: browserslist.Options & {ignore?: string[]}}} result */
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prepare(result) {
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const resultOpts = result.opts || {};
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const browsers = browserslist(null, {
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stats: resultOpts.stats,
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path: __dirname,
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env: resultOpts.env,
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});
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const initialSupport = isSupported('css-initial-value', browsers);
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return {
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OnceExit(css) {
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css.walkDecls((decl) => {
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const lowerCasedProp = decl.prop.toLowerCase();
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const ignoreProp = new Set(
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defaultIgnoreProps.concat(resultOpts.ignore || [])
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);
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if (ignoreProp.has(lowerCasedProp)) {
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return;
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}
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if (
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initialSupport &&
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Object.prototype.hasOwnProperty.call(toInitial, lowerCasedProp) &&
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decl.value.toLowerCase() ===
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toInitial[/** @type {keyof toInitial} */ (lowerCasedProp)]
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) {
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decl.value = initial;
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return;
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}
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if (
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decl.value.toLowerCase() !== initial ||
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!fromInitial[/** @type {keyof fromInitial} */ (lowerCasedProp)]
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) {
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return;
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}
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decl.value =
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fromInitial[/** @type {keyof fromInitial} */ (lowerCasedProp)];
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});
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},
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};
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},
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};
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}
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pluginCreator.postcss = true;
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module.exports = pluginCreator;
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